descriptive statistics

• what are descriptive statistics? 


  descriptive statistics are to know what measures of central tendency to use, analyse and interpret quantitative data
• what are the 2 types of data?

  quantitative data- numerical

  qualitative data- words
• what is primary data?


  this is collated by some people other than the researcher, this can or cannot be for that researcher
• what is secondary data?


  1st hand data, for the researcher
• what is a meta analysis? 


  this is where you get bigger numbers for your sample of people, this makes it easier to generalise it. this is always secondary data
• what is the mode? 


  the mode is used to measure numerical data. this is the most common number in the sample.
• what is positive about the mode?


  this is very easy to calculate compared to the others
• what is negative about the mode?


  this is a very crude measure, its often not representative of the whole data set. several modes are not useful
• what is the mean? 


  the mean is used for interval data. this is where you add up all the numbers and divide them by how many there is
• what is positive about the mean? 


  this is the most sensitive measure as it uses all of the data, therefore this is more representative of the data as a whole.
• what is negative about the mean? 


  it can be seriously distorted by extreme values, this may not end up representing the data well
• what is the median?


  the median is used to measure ordinal data. we put the numbers in order, biggest to smallest, and find the middle. if there are 2 numbers in the middle then we add them together and divide them by 2
• what is positive about the median? 


  this is not affected by extreme values
• what is negative about the median? 


  this is less sensitive than the mean as it doesn't take into account all the values. the extreme values, which it doesn't consider, may be important data.
• what is the range? 


  the range measures ordinal data. this is the biggest value takeaway from the smallest value
• what is positive about the range? 


  this is easy to calculate compared to standard deviation, as you just have to do the highest minus the lowest
• what is negative about the range? 


  the range only looks at extreme values which may be unrepresentative of the data. it doesn't show whether the numbers in the data are set closely grouped around the mean or all spread out, which is what the standard deviation does.
• what is positive about the measure of dispersion? 


  its more precise and a more sensitive measure than the range as it includes all the data in the calculation and is more representative of the data as whole.
• what is negative about the measure of dispersion?


  as it includes all the data, it can be distorted by a single extreme value